Hydrothermal synthesis spherical TiO2 and its photo-degradation property on salicylic acid

Anatase TiO2 spheres have been prepared using hydrothermal synthesis. The prepared spheres were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and UV–vis diffuse reflectance spectra (UV–vis DRS). The TiO2 consisted of well-defined spheres with size of 3–5 μm. The photocatalytic activity of spherical TiO2 was determined by degradation of salicylic acid under visible light irradiation. It was revealed that the degradation rate of the spherical TiO2 which was processed at 150 °C for 48 h could reach 81.758%. And the kinetics of photocatalytic degradation obeyed first-order kinetic, which the rate constant value was 0.01716 S−1 of the salicylic acid onto TiO2 (temperature: 150, time: 48 h). The kinetics of adsorption followed the pseudo-second-order model and the rate constant was 1.2695 g mg−1 of the salicylic acid onto TiO2 (temperature: 150, time: 48 h).